1. Field of the Invention
This invention relates to compounds having anti-thrombotic activity. More particularly, the invention relates to novel peptides and pseudopeptides that inhibit platelet aggregation and thrombus formation in mammalian blood and are useful in the prevention and treatment of thrombosis associated with disease states such as myocardial infarction, stroke, peripheral arterial disease and disseminated intravascular coagulation.
Haemostasis, the biochemistry of blood coagulation, is an extremely complex and as yet not completely understood phenomena whereby normal whole blood and body tissue spontaneously arrest bleeding from injured blood vessels. Effective haemostasis requires the combined activity of vascular, platelet and plasma factors as well as a controlling mechanism to prevent excessive clotting. Defects, deficiencies, or excesses of any of these components can lead to hemorrhagic or thrombotic consequences.
Platelet adhesion, spreading and aggregation on extracellular matrices are central events in thrombus formation. These events are mediated by a family of platelet adhesive glycoproteins, i.e., fibrinogen, fibronectin, and von Willebrand factor. Fibrinogen is a co-factor for platelet aggregation, while fibronectin supports platelet attachments and spreading reactions, and von Willebrand factor is important in platelet attachment to and spreading on subendothelial matrices. The binding sites for fibrinogen, fibronectin and von Willebrand factor have been located on the platelet membrane protein complex known as glycoprotein IIb/IIIa.
Adhesive glycoproteins, like fibrinogen, do not bind with normal resting platelets. However, when a platelet is activated with an agonist such as thrombin or adenosine diphosphate, the platelet changes its shape, perhaps making the GPIIb/IIIa binding site accessible to fibrinogen. Compounds within the scope of the present invention block the fibrinogen receptor, thus inhibiting platelet aggregation and subsequent thrombus formation and when administered in the form of pharmaceutical compositions comprising such compounds are useful for the prevention and treatment of thrombogenic diseases, such as myocardial infarction, stroke, peripheral arterial disease and disseminated intravascular coagulation.
2. Reported Developments
It has been observed that the presence of Arg-Gly-Asp (RGD) is necessary in fibrinogen, fibronectin and von Willebrand factor for their interaction with the cell surface receptor (Ruoslahti E., Pierschbacher, Cell 1986, 44, 517-18). Two other amino acid sequences also seem to take part in the platelet attachment function of fibrinogen, namely, the Gly-Pro-Arg sequence, and the dodecapeptide, His-His-Leu-Gly-Gly-Ala-Lys-Gln-Ala-Gly-Asp-Val sequence. Small synthetic peptides containing the RGD or dodecapeptide have been shown to bind to the platelet GPIIb/IIIa receptor and competitively inhibit binding of fibrinogen, fibronectin and von Willebrand factor as well as inhibit aggregation of activated platelets (Plow, et al., Proc. Natl. Acad. Sci. USA 1985, 82, 8057-61; Ruggeri, et al., Proc. Natl. Acad. Sci. USA 986, 5708-12; Ginsberg, et al., J. Biol. Chem. 1985, 260, 3931-36; and Gartner, et al., J. Biol. Chem. 1987, 260, 11,891-94).
Indolyl compounds containing guanidinoalkanoyl- and guandinoalkenoyl-aspartyl moieties are reported to be platelet-aggregation inhibitors by Tjoeng, et al., U.S. Pat. Nos. 5,037,808 and 4,879,313.
U.S. Pat. No. 4,992,463 (Tjoeng, et al.), issued Feb. 12, 1991, discloses generically that a series of aryl and aralkyl guanidinoalkyl peptide mimetic compounds exhibit platelet aggregation inhibiting activity and discloses specifically a series of mono- and dimethoxy phenyl peptide mimetic compounds and a biphenylalkyl peptide mimetic compound.
U.S. Pat. No. 4,857,508 (Adams, et al.), issued Aug. 15, 1989, discloses generically that a series of guandinoalkyl peptide derivatives containing terminal aralkyl substituents exhibit platelet aggregation inhibiting activity and discloses specifically a series of O-methyl tyrosine, biphenyl, and naphthyl derivatives containing a terminal amide functionality.
Haverstick, D. M., et al., in Blood 66 (4), 946-952 (1985), disclose that a number of synthetic peptides, including arg-gly-asp-ser and gly-arg-gly-asp-ser, are capable of inhibiting thrombin-induced platelet aggregation.
Plow, E. F., et al., in Proc. Natl. Acad. Sci. USA 79, 3711-3715 (1982), disclose that the tetrapeptide glycyl-L-prolyl-L-arginyl-L-proline inhibits fibrinogen binding to human platelets.
French Application No. 86/17507, filed Dec. 15, 1986, discloses that tetra-, penta- and hexapeptide derivatives containing the -arg-gly-asp- sequence are useful as antithrombotics.
U.S. Pat. No. 4,683,291 (Zimmerman, et al.), issued Jul. 28, 1987, discloses that a series of peptides, comprised of from six to forty amino acids, which contain the sequence -arg-gly-asp- are platelet binding inhibitors.
European Application Publication No. 0 319 506, published Jun. 7, 1989, discloses that a series of tetra-, penta-, and hexapeptide derivatives containing the -arg-gly-asp- sequence are platelet aggregation inhibitors.
Cyclic peptide analogues containing the moiety Gly-Asp are reported to be fibrinogen receptor antagonists in U.S. Pat. No. 5,023,233.
Peptides and pseudopeptides containing amino-, guanidino-, imidizaloyl, and/or amidino- alkanoyl, and alkenoyl moieties are reported to be antithrombotic agents in pending U.S. applications Ser. Nos. 07/677,006, 07/534,385, and 07/460,777 filed on Mar. 28, 1991, Jun. 7, 1990, and Jan. 4, 1990, respectively, as well as in U.S. Pat. No. 4,952,562, and in International Application No. PCT/US90/05448, filed Sep. 25, 1990, all assigned to the same assignee as the present invention.
Peptides and pseudopeptides containing amino- and guanidino- alkyl- and alkenyl-benzoyl, phenylalkanoyl, and phenylalkenoyl moieties are reported to be antithrombotic agents in pending U.S. application Ser. No. 07/475,043, filed Feb. 5, 1990, assigned to the same assignee as the present invention.
The present invention relates to novel peptides and pseudopeptides which inhibit platelet aggregation and subsequent thrombus formation.